Through a non-Volvo friend of mine I may have a connection to acquire for very low cost an old B-18 and (presumably) M40 tranny of ~63 vintage. The tranny I'm told is tight and mechanically fine. The engine has been exposed to the elements (don't know for how long) with neither a hood nor a valve cover to protect it. Of course, I don't need either of these items but I'm intrigued none the less. Some questions -

Is this transmission likely to be an 'identical' swap for any other B-18 transmission in say a later model Duett or 544? My understanding is that transmissions are essentially the same but rear ends have different gear ratios.

As far as the engine is concerned (I haven't seen it yet), is there any chance it's rebuildable or would it be too far gone. Is it worth rebuilding a B-18 at all or, if changing engines anyway, should I go straight for a B-20?

Lastly, is the transmission compatible with a B-20?

Many thanks for your thoughts.

KaiS
'67 Duett